We just tested two samples of Evetar N123B05425W lens that is very similar to Sunex DSL945D described in the previous post.
|Sunex DSL945D||Evetar N123B05425W|
|IR cutoff filter||yes||yes|
|Recommended sensor resolution||10Mpix||10MPix|
Both lenses are specified to work with 10 megapixel sensors, so it is possible to compare “apples to apples”. This performance comparison is based only on our testing procedure and does not involve any additional data from the lens manufacturers, the lens samples were randomly selected from the purchased devices. Different applications require different features (or combination of features) of the lens, and both lenses have their advantages with respect to the other.
Sunex lens has very low longitudinal chromatic aberration (~5μm) as indicated on “Astigmatism” (bottom left) graphs, it is well corrected so both red and blue curves are on the same side of the green one. Evetar lens have very small difference between red and green, but blue is more than 15 μm off. My guess is that the factory tried to make the lens that can work in “day/night” applications and optimized design for visible and infrared spectrum simultaneously. Sacrificing infrared (it anyway has no value in high resolution visible light applications) at the design stage could improve performance of this already very good product.
Petzval field curvature of the DSL945D is slightly better than that of the N123B05425W, astigmatism (difference between the sagittal and the tangential focal shift for the same color) is almost the same with maximum of 18 μm at ~2 mm from the image center.
Center resolution (mtf50% is shown) of the DSL945D is higher for each color, but only in the center. It drops for peripheral areas much quicker than the resolution of the N123B05425W does. Evetar lens has only sagittal (radial) resolution for blue component dropping below 100 lp/mm according to our measurements, and that gives this lens higher full-field weighted resolution values (top left plot on each figure).
Lens testing data
The graphs below and the testing procedure are described in the previous post. Solid lines correspond to the tangential and dashed – to the sagittal components for the radial aberration model, point marks account for the measured parameter variations in the different parts of the lenses at the same distance from the center.